I just did this on dad's '85, so here's the hints from that.

1 - inspect the new harness carefully and each connector before installing it on the sensor, etc where it goes. If one connector gets damaged, etc and does not make contact in the installation process or before, it's a bear to find later.

2 - label the old harness and remove it in one piece.

3 - clean flame trap, oil box, throttle body (remove to install harness, it saves time) and replace temperature sensor for FI while in there. it's cheap. It's easy to get to when you do this job.

4 - alternator wires are a pain to do. be patient.

5 - clean all the grounds and use a dielectric grease when reinstalling.

6 - remove the amm, all the air ducts, the distributor cap and rotor whn doing the job.

7 - now is a dandy time to replace your oxygen sensor. Just as easy to do as the rest of the time, but it's a good maintenance issue.

as a total noob at harnesses, this took me 4 consecutive hours. Allow enough time to do the job start to finish, and with as few breaks as possible. After 4 hours, you will be able to look at the harness you just pulled and know where everything goes without even looking at the labels you put on.

Jim